Project Summary Couples HIV testing and counseling (CHTC) for male couples in the US has emerged as a promising dyadic HIV prevention strategy. Interventions such as CHTC, which address HIV-risk within primary relationships, are an essential component to a comprehensive national prevention strategy. Up to two-thirds of HIV infections among MSM occur within the context of primary partnerships. Rates are particularly pronounced for emerging adult MSM (aged 18-29). Estimates suggest 79% to 84% of HIV infections are transmitted by primary partners5. The current CHTC protocol is limited in two ways. First, CHTC does not incorporate a focus on drug use ? a well-established correlate of HIV infection risk among YMSM specifically. Second, CHTC provides limited guidance for formal communication skills training in instances where partners have substantial communication deficits. To address these limitations, our group has developed and pilot-tested the We Test intervention, which includes two adjunct CHTC components. The first is a substance use module (SUM) that elicits the formation of a substance use agreement and a discussion about how partners can support one another in observing drug use limits. The second is an assertive communication training video (ACTV). Results from our recent pilot RCT (DA036419, PI-Starks) suggest these components decrease the odds of drug use and drug-related problems. We now propose a multi-site trial powered to test the efficacy of We Test?s components and evaluate putative moderators and mediators. The proposed RCT builds directly upon the pilot data generated by DA036419. Participants include 240 male couples in which at least one partner is age 18 ? 29; HIV negative; and reports recent (past 30 days) drug use; and recent (past 3 months) sexual HIV/STI transmission risk behavior. The study utilizes biological markers for drug use (fingernail assay), HIV testing, and gonorrhea, chlamydia, and syphilis. Viral load testing is conducted with HIV positive participants. To increase generalizability and the feasibility of recruitment, couples be enrolled equally across 2-sites in New York City and Detroit. Participants will be randomized in a factorial design to receive CHTC as usual; CHTC + SUM; CHTC + ACTV; or CHTC+SUM+ACTV. Follow-ups will occur at 3-, 6-, 9-, and 12-months post intervention. Drs. Starks, Stephenson (Co-I), Kahle (Co-I; biostatistician) and Sullivan (Consultant) have substantial experience in the study of male couples. This group completed the pilot RCT which produced the formative data for this proposal. The study is supported by the Emory CFAR Prevention Sciences Core and the Clinical Virology Research Laboratory. The intervention tested is an innovative and highly scalable adaptation of the existing CHTC intervention. In addition, the integration of a substance use intervention into CHTC might facilitate uptake by affording access to additional funding sources and expanding the pool of providers who see the service as relevant. Results would inform the development of a future implementation/effectiveness trial. .